It’s time for We Are Social’s Monday Mashup, our pick of some of the web’s finest social media developments.

PleaseRobMe.com reveals dangers of social networks
If you’re a heavy user of Foursquare and Twitter, you might want to take notice of PleaseRobMe.com.The website made the headlines by highlighting in real-time the whereabouts of people who checked in on Foursquare and shared their location on the web via Twitter. The goal of the three Dutch developers who set up the site was to highlight the dangers of publicly telling others your location on the Internet because it “ leaves one place you’re definitely not… home.”

The goal of this website is to raise some awareness on this issue and have people think about how they use services like Foursquare, Brightkite, Google Buzz etc. Because all this site is, is a dressed up Twitter search page. Everybody can get this information.

While traffic figures are important, the blog notes that the real story is around user engagement and on this front Facebook wins hands down:

Check out how monthly Attention (time spent on Facebook.com as a percentage of all time spent online each month) ramps over the past year for Facebook, while both Yahoo and Google show a decrease. In January, 11.6% of all time spent online was spent on Facebook (compared to 4.25% for Yahoo and 4.1% for Google).

The recent launch of Google Buzz is no doubt aimed at eating into the amount of time that users spend on Facebook, but time will tell if Google can be successful here.

… when you search for anything on Google, as part of your search results you will see live updates from MySpace users, including news, photos, and blog posts that they have chosen to publically publish. Further, all of these updates will be ranked to reflect the freshest, most relevant results, making it easier to find the latest information on anything you’re searching for on Google, including the music and artists you enjoy most.

MySpace now joins Twitter as one of the services that are now live in Google’s real-time search, announced last year.